Hi everyone. I apologize for the length of this post. I'm trying to be thorough.

About a month ago I began to notice a strange smell in my house. It has grown stronger, but sometimes is undetectable, sometimes very strong. I cannot pinpoint it to a specific location or room, and it circulates through the vents. Sometimes. Often I notice it but friends don't, then at other times they do.

-At first I thought it was electronic components because I first smelled it in my home office and it seemed like electric plastic smell of a new component out of the box. I tried disconnecting some of my electronic components. This did not make a difference.
-I thought it might be faulty wiring in the walls. I got an electrician to check the plugs in rooms where odour was strongest. No problems there.
-I evacuated my cat to a friend's place in case it's gas and that could hurt her before me. It is not a cat smell, btw.
-Fridge? Had a technician check it out but he said it was working perfectly.
-Water heater? A technician did not find anything wrong. I think he checked only for CO leaks.
-Gas furnace? Tech said it was working fine.
(-Later we found problems with the furnace and tech fixed a condensation reservoir. But he said it was not related to the smell--though he couldn't detect the smell himself.)
-I had a quick indoor air quality check done. It found no elevated levels of anything except VOCs, but they were not terribly high--not in the red zone of the metres by any means. I will get a more comprehensive test if I can't sort this out myself (those test cost hundreds of dollars).
-I had a water leak in my bathroom above my front foyer a few weeks before I smelled it. I cut into the ceiling to see if any mold or smell was coming from there, but there was nothing. I had a contractor friend check it out, too, and he said the space was dry and fine.
-I had a mold expert/home air quality inspector come in. He didn't find anything that would be causing this.
-Ducts were cleaned and a disinfectant sprayed in them. Randy the duct cleaner who is also a water heater and furnace installer, said the problem may be the venting of the water heater into the chimney. He said there may be a creature dead in the chimney, restricting the venting, so then exhaust flows back into the house and is circulated by the furnace which is right beside the chimney vent, but vents to the side of the house.
-He will also come to clean the furnace but he doesnít think thatís the furnace is the problem.
-I then tried an experiment by not running my hot water all day to see if there was a smell. I caught a mild one, but that may have been because the water heater turns on at various times to reheat the water.
-But some days when I'm not using a lot of hot water the odour is quite powerful
-I have noticed that a few times the smell was especially strong when the sun was shining. Could this have something to do with the chimney?
-It is not coming from outside since it has appeared when the wind is blowing from different directions
-One day it was slightly warmer (just above freezing) I opened some windows to air the place out. When I got home the odour was quite strong. I thought it might be the furnace because it would have been on longer that day. It was also sunny that day (see above)
-The smell alternates between being a slight organic smell, (perhaps rotting animal confirming Randy's theory? but not super strong), and a more mechanical smell, almost like a refinery.
-When it is strong, my eyes get irritated, and I can almost taste it in the air. It may be an illusion, but it feels as if the air is heavier at those times.
-As I noted earlier, it began as something decidedly electronic.

Any help, suggestions, ideas, advice, references... please contact me or post here!! I'm losing what's left of my mind. And since I work at home, I get it 24/7!

joecaption

03-24-2013 11:53 AM

How old is the house?
Ballon wall constrution?
Has there been any drywall work done there in the past?

Larryh86GT

03-24-2013 01:12 PM

It could be a dead critter in a wall, crawlspace, attic, or basement. Or a dead bird could be in your chimney flue. I found one in mine before I had a high efficiency furnace put in. If it's cold they like to sit on top of the chimney and warm up and the carbon monoxide knocks them out. Or it could be something else making the odor.

DanJM

03-24-2013 01:43 PM

More info

Thanks for the questions
Home is about 100 years old.
I don't know what a balloon wall construction is.
I did some drywall about five or six years ago on an internal wall. that's all the major indoor construction I've done.
Basement is rough stone wall and concrete floor (FWIW)

oldhouseguy

03-24-2013 07:38 PM

You can shut the water heater off completely for 24 hours and see if you smell it at all.

If you do, it isn't that.

If you don't it is.

I had a rat come through a sewer pipe into a dry toilet once. And then it died in the basement.

You would know if it was something like that. It wouldn't be a mechanical smell.

It would be the smell of death.

Windows on Wash

03-25-2013 09:45 AM

+1

Being a balloon framed home, there are any number of spots for critters to enter and get into stuff.

See if you can narrow the search by systematically eliminating areas of consideration.

ToolSeeker

03-25-2013 10:28 AM

MY suggestion would be if you get a nice day shut the furnace off and the hot water heater off, shut up each room you can then go room by room and try to pin point where it is coming from. Then if you can't tell turn on the water heater alone and see if that makes a diff. Kind of eliminating the spaces one at a time.

DanJM

03-25-2013 08:55 PM

Thanks for all of these suggestions. I don't know how to turn off the water heater (I'm a little wary of gas) but do with the furnace.

I still don't know what a balloon frame construction is.

Today it was a very strong warm transformer-type smell. It wafted through the house all afternoon. :wallbash:

Larryh86GT

03-25-2013 09:39 PM

I think at this point I would get an electrician in to try to pinpoint the issue. A very strong warm transformer-type smell sounds electrical and may be serious.

DanJM

03-25-2013 09:48 PM

Thanks. I know, it does sound serious. I did get an electrician in and (before over charging me) he said that if it were a transformer, it would have blown or burned itself out by now. Cold comfort, but it has not done that. I'm still waiting for the chimney cleaning and furnace cleaning. Who knows, it may be the solution... I've kind of given up hope though. :(